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Smart Materials Research
Volume 2012 (2012), Article ID 258638, 7 pages
http://dx.doi.org/10.1155/2012/258638
Research Article

Magnetostrictive Actuation of a Bone Loading Composite for Accelerated Tissue Formation

Department of Mechanical & Aerospace Engineering, The Ohio State University, E307 Scott Laboratory, 201 West 19th Avenue, Columbus, OH 43210, USA

Received 27 May 2011; Revised 28 September 2011; Accepted 2 October 2011

Academic Editor: Osama J. Aldraihem

Copyright © 2012 Stephen Hart et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

When bone is dynamically loaded it adapts its shape to better support the load. We have developed a magnetostrictive composite consisting of Terfenol-D particles encapsulated in an epoxy resin that changes length when exposed to magnetic fields. When bonded to the surface of a porcine tibia ex vitro, the composite produces surface strains greater than 900 με at a frequency of 30 Hz and magnetic field of 170 kA/m. This is more than sufficient strain magnitude and frequency to promote cortical bone growth in both rats and turkeys and to maintain cortical bone structure in humans. Key advantages of the composite over conventional electromechanical or thermomechanical actuators are its simplicity, compact size, and remote actuation. A mathematical model describing the strains and stresses in the bone is presented.